Method for installing closure in mouth of pre-made bag

Abstract

A method for installing a closure in the mouth of a pre-made flexible bag. The closure may, for example, be a shrouded plastic zipper with or without a slider. The bag may, for example, have side gussets. In the disclosed embodiment, the bag is made using a laminated material comprising an interior layer of thermoplastic material and a non-interior layer of non-thermoplastic material, such as paper. The package is made by a method comprising the following steps: method for providing a bag with a closure, comprising the following steps: (a) slitting the bag along first and second lines so that a top marginal portion of one wall of the bag disposed between the first and second lines forms a flap; (b) folding back the flap to uncover a topmost portion of the other wall; (c) joining one side of a closure to at least a portion of the topmost portion of the other wall uncovered by step (b); and (d) joining a portion of the flap to the other side of the closure after steps (a)-(c) have been performed.

1. A method for providing a gusseted bag made of a laminated material with a closure comprising a folded web of thermoplastic material, said laminated material comprising an interior layer of thermoplastic material and a non-interior layer of non-thermoplastic material, said method comprising the following steps:
 (a) slitting the gusseted bag along first and second lines so that a top marginal portion of one wall of the bag disposed between said first and second lines forms a flap; 
 (b) arranging the top of the gusseted bag so that the topmost portions of the gussets on each side are not expanded and the flap does not cover the topmost portions of a respective gusset panel of a respective gusset or the topmost portion of the other wall disposed between said respective gusset panels; 
 (c) joining one leg of said folded web of thermoplastic material to said inner layer of thermoplastic material of at least respective portions of the topmost portions of said respective gusset panels and said other wall exposed by step (b); and 
 (d) joining said inner layer of thermoplastic material of a portion of said flap to the other leg of said web of thermoplastic material after steps (a)-(c) have been performed. 
 
   
   
     2. The method as recited in  claim 1 , wherein said joining steps are performed by melting or softening respective surfaces made of thermoplastic material. 
   
   
     3. The method as recited in  claim 1 , further comprising the step of sealing at least portions of the slits formed in step (a). 
   
   
     4. The method as recited in  claim 1 , wherein said closure further comprises a zipper joined to and covered by said folded web. 
   
   
     5. The method as recited in  claim 4 , further comprising the step of joining the opposite ends of said first leg of said folded web to the respective opposite ends of said second leg of said folded web from distal edges of said first and second legs of said folded web up to said zipper. 
   
   
     6. The method as recited in  claim 1 , further comprising the steps of gluing the respective gusset panels of each gusset together near each end of the closure. 
   
   
     7. The method as recited in  claim 1 , wherein as a result of steps (c) and (d), respective zones of joinder are produced that extend along the entire length of said closure. 
   
   
     8. The method as recited in  claim 1 , further comprising the steps of joining a portion of the topmost portion of said other wall that is not joined to said folded web to a topmost portion of a gusset panel that is not joined to said folded web. 
   
   
     9. The method as recited in  claim 1 , wherein heat is conducted through both legs of said folded web and not through said flap during step (c). 
   
   
     10. The method as recited in  claim 9 , wherein the source of said heat is not in contact with said layer of non-thermoplastic material. 
   
   
     11. The method as recited in  claim 9 , wherein heat is conducted through said flap during step (d). 
   
   
     12. A method for providing a bag made of a laminated material with a closure comprising a folded web of thermoplastic material, said laminated material comprising an interior layer of thermoplastic material and a non-interior layer of non-thermoplastic material, said method comprising the following steps:
 (a) slitting the bag along first and second lines so that a top marginal portion of one wall of the bag disposed between said first and second lines forms a flap; 
 (b) folding back said flap to uncover a topmost portion of the other wall; 
 (c) joining one leg of said folded web of thermoplastic material to said inner layer of thermoplastic material of at least a portion of said topmost portion of said other wall uncovered by step (b); and 
 (d) joining said inner layer of thermoplastic material of a portion of said flap to the other leg of said web of thermoplastic material after steps (a)-(c) have been performed. 
 
   
   
     13. The method as recited in  claim 12 , wherein said closure further comprises a zipper joined to and covered by said folded web. 
   
   
     14. The method as recited in  claim 12 , wherein heat is conducted through both legs of said folded web and not through said flap during step (c). 
   
   
     15. The method as recited in  claim 14 , wherein the source of said heat is not in contact with said layer of non-thermoplastic material. 
   
   
     16. The method as recited in  claim 14 , wherein heat is conducted through said flap during step (d).